The inhibitory effect of intestinal bacterial metabolite of ginsenosides on CYP3A activity

The intestinal bacterial metabolites of ginsenosides are responsible for the main pharmacological activities of ginseng. The purpose of this study was to find whether these metabolites influence hepatic metabolic enzymes and to predict the potential for ginseng-prescription drug interactions. Utilizing the probe reaction of CYP3A activity, testosterone 6beta-hydroxylation, the effects of derivatives of 20(S)-protopanaxadiol and 20(S)-protopanaxatriol families on CYP3A activity in rat liver microsomes were assayed. Our results showed that ginsenosides from the 20(S)-protopanaxadiol and 20(S)-protopanaxatriol family including Rb-1, Rb-2, Rc, Compound-K, Re, and Rg(1), had no inhibitory effect, whereas Rg(2), 20(S)-panaxatriol and 20(S)-protopanaxatriol exhibited competitive inhibitory activity against CVP3A activity in these microsomes with the inhibition constants (K) of 86.4+/-0.8mum, 1.7+/-0.1mum, and 3.2+/-0.2 mum, respectively. This finding demonstrates that differences in their chemical structure might influence the effects of ginsenosides on CYP3A activity and that ginseng-derived products might have potential for significant ginseng-drug interactions.

森林流域洪涝灾害成因分析与防治对策

森林流域洪涝灾害成因分析与防治对策孙铁珩，裴铁璠张吉娜（中国科学院沈阳应用生态研究所）（辽宁省生态学会）本文所述的森林流域是广义的，系指我国典型敏感带以东广大地区。典型敏感带始于东北西部内蒙东部向西南一直延伸到青藏高原东南部。它是干旱、半干旱与湿润、...

土壤中难降解有机污染物锁定机理研究进展

有机污染物进入土壤后,随着与土壤接触时间的延长,被锁定在土壤中,生物可利用性下降.锁定可能导致过高估计难降解有机污染物的暴露风险,影响修复技术的实施.锁定发生的内在机制主要源于粘土矿物、有机质及非水相液体的不可逆吸附和微孔束缚,而影响土壤难降解有机污染物锁定的关键因素包括土壤物理化学性质和环境条件(湿度、温度、pH等).基于此,进一步阐明了目前土壤中难降解有机污染物锁定机理研究需要解决的问题,并对未来的发展趋势进行了展望.